alarm system



July 28, 1959 GERBER Re. 24,672

ALARM SYSTEM Original Filed. June 16, 1 955 NIGHT DAY 7' (IT l m:- In

-h 1: D 9% 13 1? 9% INVENTOR:

jfaz'y fi'erber Re. 24,672 Reissued July 28, 1959 United States Patent Ofifice 24,672 ALARM SYSTEM Harry Gerber, Glendale, Califi, assignor toSimplex Industrial Products, Inc., Glendale, CaliL, a corporation 'ofCalifornia Original No. 2,771,598, dated November 20, 1956, Serial No.515,951, June '16, 1955. Application for reissue April 28,1958, SerialNo. 732,414

8 Claims. ((31.340-276) Matter enclosed in heavy brackets appears in theoriginal patent but forms no part of this reissue specification; matterprinted in italics indicates the additions made by reissue.

This invention relates to burglar alarm systems and particularly to asystem in which a conductive tape is incorporated, fracturing of thetape by a burglar energizing a circuit to set off a bell or otherwarning device embodied in the circuit.

Burglar alarm systems of the general character re ferred to above arewidely used to warn of the entranceinto buildings by unauthorizedpersons. In such conventional electric alarm systems, the tape or tapesare installed on windows and doors so that in order to gain access tothe interior of a building breaking or jumping of a tape is necessary.Such conventional alarm systems utilize batteries as the source of D.C.current at the subscribers location, this current being used to energizea relay so as to normally maintain a bell circuit open, and a second setof batteries to operate the bell if the relay is deenergized.Consequently, there exists a con-- stant drain on the batteries so thatit is necessary to replace the batteries at frequent intervals. Thisresults. in appreciable operating and upkeep costs which is refiected inincreased charges to the store proprietors and other persons subscribingto the burglar alarm service. In the event of a run-down batterycondition, the alarm. circuit is rendered ineffective and when thissituation prevails the protection afforded by the system is nullified.Moreover, due to the fact that no time delay means is employed, jarringof the window or door, the to gusts of wind, earth tremors, etc., mayinitiate im-- mediate action of the system so that the alarm mayerroneously indicate the presence of an intruder.

Other burglar alarm systems proposed in the past have operated on A.C.current but such systems have the dis advantage that they are renderedinoperative in the event of power failure and require power supplies andstand-- by batteries at both the subscriber locationand the centrallocation.

It is an object of the present invention to obviate thedisadvantages ofthe prior burglar alarm systems referred. to above by providing a systemwhich normally is operated from a main D.C. current rectified from anA.C.v power source but has incorporated therein an auxiliary D.C.current source and an automatic switching means operative in response tocurrent failure in the main cur rent supply, to connect the system tothe auxiliary D.C.. supply which is in the nature of batteries. objectofthe invention is to provide an alarm system which operates under lowD.C. current, the A.C. power supply being transformed and rectified forthis purpose.

Another object of the invention is to provide a burglar alarm system, ofthe character referred to, in which the switching means operates tore-connect the systemv to the main power source when the power isrestored. By this provision, the batteries of the auxiliary supply, areconserved so that they will remain active over a long period of time.

A related.

Another object of the invention is to provide an alarm system whichembodies a hell or other electric warning device, and a relay forcontrolling the energization of the bell circuit, the relay including abell switch normally maintained open by the relay coil so as to renderthe bell circuit inactive, deenergization of the relay coil allowingclosing of the switch to energize the bell circuit and thus effectringing of the bell or other warning device. In accordance with thepresent concept, the alarm system also includes a vibrator device havinga pair of poles, the first pole being connected to the current sourceand the second pole being connected, through a switch, to the relaycoil, the oscillating vibrator arm being arranged when in contact withthe first pole, to convey current through a pair of conductive tapesconnected in series and thence to ground. When the vibrator arm is inits other position, it is adapted to convey current to the relay coil toenergize the same.

As a particular feature and object of the invention, a first electricstorage means in the form of a condenser is connected in series in thecircuit between the tapes and a second condenser of less capacity thanthe first condenser is connected across the bell relay coil. By thisprovision, during actuation of the vibrator arm electric charges arecaused to flow intermittently from the supply line to the firstcondenser to be stored therein, when the arm contacts the first pole ofthe vibrator device. At each contact of the arm with the second pole,the electric charge stored in the first condenser is released to flow tothe bell relay coil so as to maintain the bell circuit open. At the sametime, a certain amount of the electric charge in the second condenser isthen released to maintain the bell relay coil energized when thevibrator arm disengages the first pole to again contact the second pole.Thus, the condensers are activated successively to maintain the bellrelay energized and this condition will exist so long as the conductivetapes remain unbroken. Upon fracture of a tape or jumper between tapes,the first condenser circuit is opened or :shorted so that energizationof the bell relay is disrupted to allow closing of the bell-circuit toeffect ringing of the warning bell. This eliminates the need forbatteries :at the subscribers end.

Another object of the invention is to provide a'burglar alarm systemembodying means by which the system may be conveniently renderedoperative for night duty and tie-activated during the day. This meansconsists of a control switch having a first, day contact connected tothe bell relay coil and a second, night contact connected to thevibrator unit, the actuator arm of the switch being electricallyconnected to the main current line .atall times. By this specificarrangement, throwing .of the control switch to its night side effectsenergization :of the vibrator unit to activate the bell-relay and thusinactivate the alarm bell, and throwing of the switch to its day sidecauses inactivation of the vibrator unit but energization of the bellrelay so as to maintain its bell switch open.

Further objects of the invention will appear from the followingdescription and from the single drawing which is intended for thepurpose of illustration only and which is an electrical diagram of theburglar alarm system.

Referring to the drawing in detail, the electrical systern includes atransformer T1, the input side of which relay K-l has its coil 5connected to the power line I to normally maintain the actuator arm ofthe switch 8-1 in engagement with the contact 4. The other contact 3 isconnected to a battery B. During normal conditions, the 6 V. DC current1s supplied to the line 2 through the switch S-l, the actuator arm ofwhich normally engages contact 4 in response to the continuousenergization of the relay T-1. In the event of failure of the main powersupply, the relay K-l is deenergized to allow shifting of the actuatorarm to the contact 3 so as to automatically connect the battery B to themain current line 2. Thus, the relay switching unit K-l renders thealarm system fool-proof by preventing inactivation of the system in theevent of main power failure.

The line 2 is connected to the actuator arm of a bell switch S-2 havingcontacts 6 and 7, the former being connected to a pole of an alarm bellA grounded at 8. The bell switch 8-2 is controlled by a bell relay K-2having a coil 9, one side of which is connected by a wire 10 to thecontact 11 of a second switch S-3 also controlled by the relay K-Z.Connected across the relay coil 9 is a first condenser or capacitormeans C-2.

The system also includes a vibrator unit E-l having a vibrator arm 12oscillatable between contacts 13 and 14. The vibrator unit E-l is of awell known construction and is shown only diagrammatically. The vibratorunit 13-1 is grounded at 1-5 and is energized from the line '2 through awire 16 connected to the actuator arm 17 of a day-night control switchS4. This switch has a day contact 18 connected to the wire 10 and anight contact 19 connected to the vibrator unit E-l. When the switch 8-4is closed through contact 19, current flows to the vibrator unit toenergize the same and thus oscillate the arm 12 to successively engagethe contacts 13 and 14. The contact 13 is electrically connected to themain current line 2 so that upon momentary engagement thereof by the arm12, current is caused to flow through'a line 20 to one end of aconductive tape t-l. The tape t-1 is connected to a second grounded tapet-2 by a wire 21 in which is interposed a second condenser or capacitormeans -3. It is to be noted that the condenser C-3 has twice thecapacity of condenser C-2. Contact 14 of the vibrator unit E-l isconnected by a wire 22 to the actuator arm of relay switch -3. Groundconnections areshown for simplification only and may be replaced byconnecting all grounds together with a wire.

Assuming that the line 2 is being supplied with current from either thetransformer T-1 or the battery B, and that the control switch S4 isclosed through its day contact 18, current flows from line 2, arm 17 andcontact 18 to wire so as to energize-the bell relay K-2 and thus causethe switches S-2 and 8-3 to assume the positions shown in the drawing.

To set the system for operation, the control switch S4 is shifted toclose the night contact 19 and during this shifting the holding relayK-2 maintains the switches S-2 and 8-3 in the positions shown. Closingof the switch S4 through the contact 19 energizes the vibrator unit E-1to oscillate its arm 12.

Momentary engagement of the arm with the contact 13 causes current flowthrough the tape t-l to charge the condenser C-3 [and through the wire21 and condenser 0-3 to the second tape t-2 and hence to ground. Duringthis momentary flow of current through the tapes, a charge ofelectricity is stored up in the condenser (3-3]. Now, as the arm 12 nextmomentarily engages contact 14, [the charge of electricity is releasedby the condenser (3-3 and flows to the'relay coil 9] the condenser C-3discharges by Way of line 22, closed switch S-3 and wire 10 to energizethe relay coil 9. The condenser C-2 holds the relay energized betweensuccessive engagements of the vibrator arm 12 with the contact 14. It isthus seen that during one stroke of the vibrator arm 12, electricpotential is accumulated in the condenser C-3 and at the completion ofthe oscillatory stroke of the arm in the other direction the charge isdischarged to flow to the relay coil 9 and condenser C-2. "Before theholding relay can become deenergized, another charge of current isdelivered thereto.

This intermittent energization of the bell relay K-2 continuesthroughout the night hours to maintain the circuit to the bell A open.In the event that either tape t-1 or t-2 is broken or a jumper connectedbetween t-1 or t-2, the circuit through the tape is opened or 0-3 isshorted so that storing of electric potential in the condenser C-3 isimpossible. Consequently, when this situation occurs, the relay K-2 isdeenergized to allow closing of the hell circuit through the switchcontact 6 so as to activate the alarm bell A. At the same time, a bell,light or other warning device on a master panel located remotely fromthe scene may be activated through a telephone line connected to thebell circuit. The alarm will, of course, remain energized until thebroken tape is repaired and switch S4 returned to the-day position toreset holding relay K-2.

It is to be observed that the condenser C-2 serves two purposes, thatis, to hold the relay K-2 energized while the condenser C-3 is beingcharged and to provide a time delay so as to avoid accidental settingoff of the alarm in the event of temporary opening of the tape circuitdue to gusts of wind, earth tremors, etc.

During the day, the alarm system is rendered inoperative by simplyshifting the control switch 5-4 to close the circuit through day contact18. Current thus flows directly from line 2 to the relay K-2 which actsto maintain the bell switch S-2 open.

As previously indicated, failure of the main power sup ply P results inautomatically closing the switch S-1 through its contact 3 so as toefiect current flow from the battery B to the system. When power isrestored, the switch is actuated by the relay K-l tore-connect the line2 to the transformer T-1. Thus, the battery B is employed only as anemergency source of electric current so that it will last over a longperiod of time. Since fre quent replacement of batteries is unnecessary,replacement costs and service charges are reduced to a minimum. Further,in present conventional systems, batteries are necessary, in place ofC-3, to protect against jumpering of t-1 to t-2, but in the improvedsystem remote batteries at the subscribers end are rendered unnecessary.In

fact, as will be apparent to those skilled in the art, not

only the battery 15 but also the switches S-I, S-2, 8-3, relay K-2,condenser C-2, switch S-4, and the vibrator unit E-I may all be at acentral station, the wire 20 being the sole connection between thesubscriber and the central station.

With reference to the terms employed in the appended claims, the circuitcomprising the vibrator arm 12, line 20, and conductor t-I may be termeda detector circuit; the vibrator E-l may be termed a cyclic switch; thecircuit that comprises the relay coil K-2 may be termed a controlcircuit; and the circuit for energizing the alarm bell A may be aptlydescribed as an alarm signal means that is responsive to the dischargeof the two capacitor means for operation whenever either capacitor meansfails to discharge, whereby the alarm signal means is normallyinoperative but operates whenever said detector circuit is broken toprevent charging of said second capacitor means.

In accordance with the provisions of the patent statutes, I have hereindisclosed the principle of the invention, together with a preferredarrangement of electrical components which I now consider to representthe best embodiment of the invention. I wish to have it understood,however, that modifications might be made therein without departing fromthe spirit or scope of the invention, as defined in the appended claims.

I claim as my invention:

1. An electric alarm system, comprising: a low voltage D.C. line; analarm device and circuit therefor, said circuit being energizable fromsaid current line; an alarm switch interposed between said circuit andsaid current line, closing of said switch effecting energization of saidalarm device; a relay operative, when energized, to maintain said alarmswitch open; a first condenser shunted across the coil of said relay; asecond relay switch having a contact electrically connected to saidrelay coil; an electric vibrator unit having a pair of spaced poles anda vibrator arm movable between the poles to alternately engage the sameto establish electrical contact therewith, the first pole beingconnected to said current line and the second pole being connected tothe actuator arm of said relay switch; an electric line connectedbetween said current line and said vibrator unit for energizing thelatter; a control switch in said electric line for opening and closingthe same; a first metallic strip electrically connected to said vibratorarm; a second metallic strip connected to ground; and a second condenserconnected between said strips, closing of said control switch causingcurrent flow to said vibrator unit to energize the same, engagement ofsaid vibrator arm with said first pole causing current flow through saidtapes and charging of said second condenser, disengagement of saidvibrator arm from said first pole and subsequent engagement of this armwith said second pole effecting discharge of the electric potential fromsaid second condenser and current flow to said first condenser and saidrelay coil so as to energize said relay and thus maintain said alarmswitch open and said relay switch closed, breaking or shorting of eitherof said metallic strips resulting in opening or shorting the circuitbetween said condensers and thus rendering said relay inactive to allowclosing of said alarm switch and energization of said alarm device.

2. An electric alarm system, comprising: a low voltage D.C. currentline; an electric alarm device connectible to said line to be energizedthereby; an alarm switch interposed between said line and said device; aholding relay operative, when energized, to maintain said alarm switchopen; an electric vibrator unit connected to said current line to beenergized therefrom, said unit having a first pole, a second pole and amovable vibrator element engagea-ble alternately with said poles, saidfirst pole being electrically connected to said current line and saidsecond pole being electrically connected to said holding relay; a lineconnected between said vibrator arm and ground; a pair of metallicstrips connected in series in said line; and an electric potentialaccumulator in said last-named line adapted to receive and store anelectric charge upon engagement of said vibrator arm with said firstpole, said potential being discharged from said accumulator to flow tosaid holding relay to energize the same upon engagement of said vibratorarm with said second pole, energization of said relay maintaining saidalarm switch open, breaking or shorting of either of said metallicstrips resulting in opening or shorting the circuit between saidcondensers and thus rendering said relay inactive to allow closing ofsaid alarm switch and energization of said alarm device.

3. A system as defined in claim 1 in which said control switch has afirst contact connected to said vibrator unit, a second contactconnected to said relay coil and said first condenser, and an actuatorarm engageable selectively with said first and second contacts andelectrically connected to said current source.

4. A system as defined in claim 1 in which said second condenser is ofhigher capacity than said first condenser.

5. In an alarm system, the combination of: a first capacitor means; asecond capacitor means; a detector circuit including said secondcapacitor means; an source; a continuously operating cyclic switch meansenergized by said E.M.F. source to connect said detector circuit withsaid first capacitor means for a first time period to discharge saidsecond capacitor means and thereby charge said first capacitor means andalternately to connect the detector circuit with said E.M.F. source fora second time period to charge said second capacitor means; means todischarge said first capacitor means during said second time period, theduration of the discharge of said first capacitor means extendingsubstantially over said second time period and the duration of thedischarge of said second capacitor means extending substantially oversaid first time period whereby the two capacitors cooperate to dischargecurrent substantially continuously; and an alarm signal means responsiveto the discharge of the two capacitor means for operation whenevereither fails to discharge, whereby the alarm signal means is normallyinoperative but operates whenever said detector circuit is broken toprevent charging of said second capacitor means.

6. A combination as set forth in claim 5 which includes switch means toconnect said source with said alarm signal means to prevent operationthereof thereby to make the alarm signal means nonresponsive to saiddetector circuit.

7. In an alarm system, the combination of: a control circuit; a firstcapacitor means for discharge to energize said control circuit; a secondcapacitor means; a detector circuit including said second capacitormeans; an' E.M.F. source; a continually operating cyclic switch meansenergized by said source to connect said detector circuit with both saidcontrol circuit and said first capacitor means and alternately with saidE.M.F. source to keep said control circuit substantially continuouslyenergized by the alternate discharge of said two capacitor means; and analarm signal means responsive to said control circuit to operatewhenever the control circuit is deenergized whereby the alarm signalmeans is normally inoperative but operates whenever said detectorcircuit is broken to prevent charging of said second capacitor means.

8. In an alarm system, the combination of: a detector circuit includinga capacitor means; an source, continuously operable means energized bysaid source to energize said detector circuit periodically foralternately charging and discharging of said capacitor means; a controlcircuit periodically energized by the discharge of said capacitor means;means to energize said control circuit periodically at time periodsalternating with the time periods of discharge of said capacitor meanswhereby the control circuit is substantially continuously energized; andan alarm signal means responsive to said control circuit to operatewhenever the con trol circuit is deenergized, whereby the alarm signalmeans is normally inoperative but operates whenever said detectorcircuit is broken to prevent charging of said capacitor means.

References Cited in the file of this patent or the original patentUNITED STATES PATENTS 2,041,540 Goldstone May 19, 1936 2,346,171 LafordApr. 11, 1944 2,473,542 Philpott June 21, 1949

